Recently, as described in Japanese Patent Application Publication No. 2004-29932 for example, electronic data are produced for manuals such as an automobile maintenance manual, which allows a huge amount of documents to be relatively easily searched and browsed. The electronic data for manuals including wiring diagrams are produced to display the manuals on a monitor screen of an electronic control system used in the automobile, the manuals being sophisticated and complicated.
The utilization of this kind of wiring diagram frequently includes the following procedure. During the failure diagnosis for example, causes of a failure are estimated from a failure event, the portion of the system that relates to the failure cause is displayed on a monitor screen, and investigation work is sequentially performed based on a system configuration displayed on the monitor screen.
Conventionally, the electronic manual is made such that the wiring diagram is prepared on the basis of system functions and is displayed on the screen. The screen can efficiently be switched between different scenes wherein connectors and pins of the wiring diagram are linked to wiring diagram of another scene. The wiring diagram is color-displayed with wiring displayed by color corresponding to the color of the wiring cord used in the car.
However, irrespective of the efforts mentioned above, the arrangement of wirings and components has become complicated with complication of the wiring diagram. Therefore, the wiring and component arrangement can hardly be visually ascertained. Even if the wiring is displayed in colors, sophisticated wiring diagram includes wirings of similar colors, making it difficult to distinguish from each other.
For cases where the cause of a failure is hard to determine, patient investigation is needed to sequentially track the wiring from a failure point to ascertain a point of cause. The wiring diagram displayed on the basis of systems is not good enough to investigate a wiring extending over plural systems.
For the circuit diagram illustrating a system relating only to brakes for example, wiring of a system relating to fuel injection is not displayed. However, in an actual wiring of a car, power supply wiring and ground wiring are common to various systems, mutually affecting plural systems.
In one example, assuming that a phenomenon called surge breakage took place, a service staff would identify the failure point by checking the automobile and finding a broken component. However, in order to identify a cause of the failure of the component, the service staff needs to estimate the cause checking connections of the whole wiring diagram of the vehicle starting from the failure point. At this point, when display of the electronic manual wiring is on the basis of systems, the investigation work would take a long time.
In contrast, the whole circuit diagram can be displayed without separating into different system, which results in a wiring diagram that is complicated and includes a large amount of information. Investigation can hardly be performed with this type of diagram even if the whole wiring diagram is scrolled on the monitor screen.